• Don't overlook our Welcome Package, it contains many links to important and helpful information about functions at VHT like posting pictures and sending PMs (private messages), as well as finding the parts you need.

    AD

350 Front Brake Problem

jakec

Veteran Member
Joined
Dec 22, 2021
Total Posts
123
Total likes
3
Location
Seattle WA
I got this 350 for my gf. The front brake was not very good. I've had a couple 350s and a 175 with the double arm system and they all had a really snappy response. Never had a problem like this before and I've rebuilt brakes without any instructions or manual or special steps. However on this bike the braking is weak and requires a strong pull on the lever.

So I rebuilt the brake, cleaning everything and putting in new shoes. But nothing changed. So I just took it apart again and followed every step you see online,

Totally rebuilt hub with new grease and shoes

Aligned brake arms with index marks on shafts

Adjusted linkage so both cams lift brake shoe in unison

Sanded shoes and hub with 100g till both had uniform clean surface

Tightened axle holders right side first with brake locked

Original brake cable in good shape

But after all that I went to test it out and it was exactly the same. In every thread that I found online the poster always goes WOW it works now! Such a big difference! So I wonder what I'm missing.
 
Sorry I can't help. From what I read you've done EVERYTHING possible, so I am also confused.

But I bet someone will come along and give you a spot on answer and we'll go, 'Why the frig didn't I think of that?':cry:
 
I got this 350 for my gf. The front brake was not very good. I've had a couple 350s and a 175 with the double arm system and they all had a really snappy response. Never had a problem like this before and I've rebuilt brakes without any instructions or manual or special steps. However on this bike the braking is weak and requires a strong pull on the lever.

So I rebuilt the brake, cleaning everything and putting in new shoes. But nothing changed. So I just took it apart again and followed every step you see online,

Totally rebuilt hub with new grease and shoes

Aligned brake arms with index marks on shafts

Adjusted linkage so both cams lift brake shoe in unison

Sanded shoes and hub with 100g till both had uniform clean surface

Tightened axle holders right side first with brake locked

Original brake cable in good shape

But after all that I went to test it out and it was exactly the same. In every thread that I found online the poster always goes WOW it works now! Such a big difference! So I wonder what I'm missing.

I suspect the shoes aren't correctly arced to the drum, quite typical for today's replacements. Follow LDR's tutorial and you'll get them right.

https://www.vintagehondatwins.com/forums/showthread.php?2573-Arcing-brake-shoes-or-linings
 
Just curious what the drum lining looks like and what does it measure?
 
Are you 100% sure the brake cable is good? If you spin the wheel and manually pull that lever does it feel different?
 
When I removed the shoes they were only worn in the middle with a slight glaze built up there. That's what I sanded off. Should the entire brake shoe be worn evenly? If not it needs to have the arc corrected?

The interior of the wheel hub is glossy and smooth. I have not measured it. But the bike has only 6,000 miles. So I doubt it's enlarged (my 350 is at 18,000 miles and has great braking).

I will try pulling on the brake actuator arm only.
 
Is there just a "good" brand I can buy that is known to have good fitment? If I have to take the brake all the way apart it's almost worth it to get the better product and install, while I'm there.
 
That’s why you been told to arch the shoes. Or don’t. After thousands of brake applications the shoes will most likely do it themselves and you’ll eventually have decent brakes. Unless you get unlucky and hi points glaze over


Sent from my iPhone using Tapatalk
 
No aftermarket linings are a "fit", they all need to be arced to get full contact. Here's the process https://www.vintagehondatwins.com/forums/showthread.php?2573-Arcing-brake-shoes-or-linings
Choices in replacement linings are EBC(UK), Vesrah(Japan) & Ferodo(Italy). Probably another one or 2 but they don't come to mind.
As you already saw, with the slight glaze on the linings, they are only making partial contact until that wears down. Because the bikes are light weight and front brakes aren't used that much this wear in can take a 1000 miles or more to occur.
 
So we actually put the shoes on last spring when we got the bike and noticed the problem. When new shoes didn't help (EBC or Vesrah from 4into1) we were like screw it, it's the middle of may let's just ride it anyways. So it has done probably about 1700 miles or so since then, when I took it apart again on monday.
 
I had the same situation with replacement rear shoes on my 450. At first they were so far out of square to the drum, right out of the package, that they would cause the backing plate to deflect when you pressed the pedal really hard. I took it apart and hand-filed them to get things better but they still only had about 20% stopping power. I thought I'd just ride it and they'd get better. After a few hundred miles it was still exactly the same, so I took it apart again and filed the high spots that were visible. Now they're up to about 30% to 40% grip but still won't lock the wheel. Because I'm a longstanding proponent of about 70% to 80% front brake use, I didn't worry about it for now... but I'll be taking the time to arc them at some point in the future.
 
Michael Morse was guy at Vintage Brake and he indeed may have closed up shop,I know he was getting up there in years. He advised doing everything guys above said plus............get wheel on a truing stand and get things true on both planes and spokes tight.Then mount spoke/brake drum assembly (thru axle bearings) in a gap bed lathe or something along those lines and turn brake drum contact surface,you do it after truing because tightening spokes can distort bore.There is a maximum diameter you have to stay under lottsa times it's stated on brake somewhere...
 
It's possible that her front wheel is slightly out of true. It create a pulsating feeling at a very small speed range about 25-30mph. I went and had it balanced and it seemed to improve a bit but it's still very faintly noticeable. It has knobby tires and they added a large weight. I would check on it now but I don't have a trueing stand. I asked for another project and the shop near me says they don't mess with trueing or building wheels.
 
Truing stands are nice...but to be honest last wheels I trued I did it by clamping axle in a vice and mounting a dial indicator on a magnetic stand. You could do same but put point of indicator on drum surface....as I remember it has to be truer than maybe you'd think,a few thousands makes a difference. Good to have shoes arced and true but if drum is out of round you're fighting a losing battle...
 
Can the drum be warped by the truing process (and unwarped) or is it that if it's warped you need to replace?

It's a dilemma because I can get a new 350 wheel for less than a truing stand (no vise or workshop bench).
 
yeah according to Michael tightening spokes would pull drum slightly out of round but could be fixed by turning in a lathe....and 50 years of heat cycles probably doesn't help either. He still has his site up and he has some tips and tricks here https://www.vintagebrake.com/tips.htm .I'm thinking if it was me and I wasn't hard and fast on a drum brake,I'd be looking for a disc to replace it,something I could get off a parts bike.
 
Yes, the drum can be warped from overtightening the spokes, usually it will relax back into round when the spokes are loosened but may take a few days before that happens.
Given that you already are dealing with a pulsation it would be wise to check the runout of the drum and get that corrected before anything else. If it won't come back to round after a few days of loose spokes then a fresh drum will be needed unless you know someone with gap bed lathe or a over 20" swing lathe, think really big machinery shop. The wheel will have to be trued before the drum can be checked or machined. The torque for the spokes is 1.4-1.8 ft. lbs.
 
I think my strategy then would be to get access to a wheel truing stand, hopefully borrowing one locally, then confirm. If the wheel is out, then try to fix, if that doesn't work, I would seek a new wheel. As I can probably find one locally for like $40. Much cheaper than any service to fix the hub and/or relacing a wheel.
 
I think my strategy then would be to get access to a wheel truing stand, hopefully borrowing one locally, then confirm. If the wheel is out, then try to fix, if that doesn't work, I would seek a new wheel. As I can probably find one locally for like $40. Much cheaper than any service to fix the hub and/or relacing a wheel.

I’ve seen people use a spare swing arm as a makeshift truing stand or maybe even be able to rig something up to use the one on the bike while on the center stand. Is that an option you have considered?


Sent from my iPhone using Tapatalk
 
The front forks make as good a truing stand as any. Block the front end up until the wheel is off the ground, zip tie or clamp a scale across the fork legs above the rim and go to work with your spoke wrench.
 
Back
Top Bottom